1. Field of the Invention
This invention relates to a liquid-cooled internal combustion engine comprising a cylinder having an axis extending between opposite ends of the cylinder, a cylinder head closing one of the cylinder ends, the cylinder being in communication with an exhaust passage axially spaced from the cylinder head, a crankshaft extending transversely to the cylinder axis and spaced from the end of the cylinder opposite the one cylinder end, a metallic housing means wherein the crankshaft is rotatably mounted, a metallic cap mounted over the cylinder head and cylinder, the metallic cap, the cylinder head and the cylinder defining a chamber for a cooling liquid, and the metallic cap having a sealing surface remote from the cylinder head and facing the metallic housing means, a piston slidably mounted in the cylinder and operatively connected to the crankshaft, the piston being operable to open and close communication between the cylinder and the exhaust passage, electric power generating means operatively connected to the crankshaft, and a lubricating oil pump operatively connected to the crankshaft and operable to discharge lubricating oil.
2. Description of the Prior Art
Such internal combustion engines are known, for example, from Austrian patent No. 121,814. According to this patent, a yieldable seal is provided between the cylinder head and the cap but there are no means for preventing the transmission of sound emanating from the area where the sealing surface of the metallic cap contacts the metallic housing means facing the sealing surface. Besides, the cap is screw-connected to the engine housing or crankcase without the interposition of sound insulating means. Therefore, the screws as well as the hard seals will transmit sound from the cylinder to the cap so that the cap will radiate corresponding sound waves. If the electric power generating means is mounted directly under the lubricating oil pump, no means is provided for preventing sound transmission from that area of the engine.